The invention relates to a device for the electrolytic surface treatment of bulk material, preferably for electrodeposition of metal from an electrolyte, with a vibrator conveyor whose conveying trough is connected to a central pipe. The conveying trough of the vibrator conveyor is arranged spirally around the central pipe and surrounded by a vessel which is provided with at least one feed and one discharge shaft for the bulk material. This vessel contains the electrolyte, into which the vibrator conveyor with the central pipe dips partially.
Since in the surface coating of bulk material with aluminum the access of air and atmospheric moisture to the electrolyte brings about a considerable reduction of the conductivity and useful life, the electroplating must be carried out in an apparatus operating under exclusion of air. In order that access of air can be prevented also during loading and unloading of this apparatus operating under exclusion of air, also feed and discharge locks are required, which may be designed as gas locks, as liquid locks, or as combined gas-liquid locks.
In a known device for mass electroplating of metal, a vibrator conveyor with a horizontal and a vertical oscillation component is provided for the transport of the bulk material through the treatment bath. Utilizing the forces of gravity, this vibrator conveyor transports the bulk material in a spiral conveying trough in ascending direction around a column type central pipe connected with the conveying trough. The conveyor together with the support column is lodged in a gasproof vessel containing an electrolyte into which the central pipe with the conveying trough dips partially. As drive means serve for example oblique-action vibrators or obliquely set rods. By such drives oscillations are caused in such a way that the bulk material is transported periodically with the oscillation, gaining height in transport direction through thee electrolyte. Such vibrator conveyors require relatively little drive force and permit gentle conveyance of the bulk material. Intensive movement and good electrolyte exchange as well as uniform current consumption over the entire effective surface of the spread-out bulk material are obtained. The conveying trough of the vibrator conveyor can be made to oscillate via the central pipe, which is connected with the oscillation drive. The central pipe then fulfills, in addition to the transmission of oscillation, also the task of a supporting structure for the conveying trough. The trough, leading spirally upward around the central pipe, is secured in an especially simple and space-saving manner on the centered central pipe. The oscillation excitation then occurs at little cost through an oscillation drive which is disposed above or below the central pipe. Current supply to the cathode occurs inside the central pipe, while the current to the anode is supplied through the vessel wall U.S. Pat. No. 4,670,120.